Due to the depletion of petroleum resources and concern about pollution, there has been increased pressure on motor vehicle manufacturers and users to provide cars which run on cleaner alternative energy sources such as electricity. Despite continuing research, however, the typical range of an electric car is presently no more than about 60 miles. This distance may be sufficient for certain commuters, however, even if the range is improved, there will remain a need to provide for recharging the vehicle remotely from the place where it is garaged.
Unlike gasoline-powered automobiles, for which numerous service stations are now conveniently located, such an infastructure would be difficult and time-consuming to install for electric vehicles, especially as such vehicles are phased in and, consequently, small in number. Moreover, although electricity is a commonly available resource, the recharging of an electric car's battery will take a relatively long time as compared to the time required to fill the tank of a gasoline-powered car. Thus, an electric service station might require a large number of charging areas, and each customer may have to wait an inordinately long time at a place where they do not wish to spend time.
There have been proposals to simply swap an old battery for a new one at such stations, however, this presents problems of its own, including the fact that the recipient of the new battery cannot be guaranteed of the quality of the exchanged unit, which may lead to operating problems and liability issues. Even if charging stations are located in convenient places, such as in shopping or working areas, the operator may wish to know the status of the charging process in order to allocate time accordingly.